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FXUS06 KWBC 082007
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST THU DECEMBER 08 2016
6-10 DAY OUTLOOK FOR DEC 14 - 18 2016
TODAY`S MODELS EXHIBIT FAIRLY GOOD AGREEMENT ON THE PREDICTED 500-HPA HEIGHT
PATTERN. A STRONG RIDGE IS PREDICTED OVER SOUTHWESTERN ALASKA. DOWNSTREAM OF
THIS RIDGE, CYCLONIC FLOW AND BELOW TO MUCH BELOW NORMAL HEIGHTS ARE PREDICTED
ACROSS THE NORTHERN CONUS. SLIGHTLY ABOVE NORMAL HEIGHTS ARE FORECAST FARTHER
TO THE SOUTH OVER THE SOUTHERN TIER OF THE CONUS. ENSEMBLE SPREAD IS MODERATELY
HIGH OVER THE WESTERN CONUS, WHERE HEIGHTS ARE GENERALLY PREDICTED BY TODAY`S
MODELS TO BE LOWER RELATIVE TO YESTERDAY`S MODEL SOLUTIONS. ENSEMBLE SPREAD IS
ALSO MODERATE TO HIGH OVER ALASKA IN ASSOCIATION WITH THE RIDGE PREDICTED OVER
WESTERN PORTIONS OF THE STATE. THE GREATEST WEIGHT IN TODAY`S MANUAL, 500-HPA
HEIGHT BLEND WAS GIVEN TO THE 0Z ECMWF ENSEMBLE MEAN SOLUTION BASED ON
CONSIDERATIONS OF RECENT SKILL AND ON ANALOG CORRELATIONS, WHICH MEASURE HOW
CLOSELY THE PREDICTED PATTERN MATCHES CASES THAT HAVE OCCURRED IN THE PAST.
BELOW NORMAL TEMPERATURES ARE STRONGLY FAVORED ACROSS THE NORTHERN TIER OF THE
CONUS AS WELL AS MUCH OF THE CENTRAL CONUS UNDERNEATH PREDICTED CYCLONIC FLOW
AND BELOW NORMAL HEIGHTS. PREDICTED NEAR TO ABOVE NORMAL HEIGHTS LEAD TO
ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE
SOUTHWESTERN CONUS AS WELL AS MUCH OF THE FLORIDA PENINSULA. ANOMALOUS
NORTHERLY FLOW AHEAD OF THE RIDGE PREDICTED NEAR SOUTHWESTERN ALASKA FAVORS
BELOW NORMAL TEMPERATURES FOR MUCH OF SOUTHERN MAINLAND ALASKA AS WELL AS THE
PANHANDLE. HOWEVER, ABOVE NORMAL TEMPERATURES ARE FAVORED UPSTREAM OF THE
PREDICTED RIDGE FOR PARTS OF THE ALEUTIANS. ABOVE NORMAL TEMPERATURES ARE ALSO
FAVORED FOR EXTREME NORTHERN ALASKA CONSISTENT WITH DYNAMICAL MODEL GUIDANCE.
THE RIDGE PREDICTED NEAR SOUTHWESTERN ALASKA AND ASSOCIATED SURFACE HIGH
PRESSURE FAVORS A DRY PATTERN OVER MUCH OF SOUTHERN ALASKA. TELECONNECTIONS
FROM THE PREDICTED 500-HPA POSITIVE HEIGHT ANOMALY CENTER NEAR SOUTHWESTERN
ALASKA FAVORS ABOVE MEDIAN PRECIPITATION DOWNSTREAM OVER MUCH OF THE WEST COAST
OF THE CONUS. ENHANCED PROBABILITIES FOR ABOVE MEDIAN PRECIPITATION ARE ALSO
INDICATED FOR MUCH OF THE NORTHERN TIER OF THE CONUS AS WELL AS THE EASTERN
SEABOARD UNDERNEATH PREDICTED CYCLONIC FLOW. BELOW MEDIAN PRECIPITATION IS
FAVORED FOR MUCH OF THE SOUTH-CENTRAL CONUS CONSISTENT WITH BOTH DYNAMICAL
MODEL GUIDANCE AND ANALOGS FROM THE MANUAL BLEND.
TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 20% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF
TODAY`S OPERATIONAL 0Z GFS CENTERED ON DAY 8, 5% OF TODAY`S OPERATIONAL 6Z GFS
CENTERED ON DAY 8, 30% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8,
5% OF YESTERDAY`S 12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7, AND 15% OF
TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD OVERALL AGREEMENT AMONG THE VARIOUS MODELS AND TOOLS.
8-14 DAY OUTLOOK FOR DEC 16 - 22 2016
DURING THE 8-14 DAY PERIOD, THE BLOCKING RIDGE FORECAST OVER THE BERING STRAIT
IS PREDICTED TO REMAIN. DOWNSTREAM OF THIS RIDGE, CYCLONIC FLOW AND BELOW
NORMAL HEIGHTS ARE GENERALLY FORECAST OVER THE NORTHERN CONUS. HOWEVER, THERE
ARE SIGNIFICANT DIFFERENCES AMONG THE MODELS REGARDING THE MAGNITUDE AND AREAL
EXTENT OF THE PREDICTED BELOW NORMAL HEIGHTS. TODAY`S GFS AND CANADIAN ENSEMBLE
MEANS FORECAST BELOW NORMAL HEIGHTS ACROSS THE NORTHERN THIRD OF THE CONUS
WHILE TODAY`S 0Z ECMWF ENSEMBLE MEAN RESTRICTS THE AREAL EXTENT TO THE
U.S./CANADIAN BORDER. THE DETERMINISTIC 0Z AND 6Z GFS, MEANWHILE, FORECAST WELL
BELOW NORMAL HEIGHTS OVER MOST OF THE CONUS. FARTHER TO THE SOUTH, THE ENSEMBLE
MEAN SOLUTIONS PREDICT NEAR TO ABOVE NORMAL HEIGHTS ACROSS THE SOUTHERN TIER OF
THE CONUS BUT DIFFER IN THE ORIENTATION OF THE HEIGHT ANOMALY PATTERN. THE 0Z
ECMWF ENSEMBLE MEAN FORECASTS THE STRONGEST POSITIVE HEIGHT ANOMALIES OVER THE
SOUTHWESTERN CONUS WHILE THE 0Z CANADIAN ENSEMBLE MEAN FORECASTS A TROUGH OVER
THE SOUTHWEST AND RIDGING DOWNSTREAM NEAR THE SOUTHEASTERN CONUS. TODAY`S GFS
ENSEMBLE MEAN SOLUTIONS GENERALLY REPRESENT A COMPROMISE BETWEEN THE TWO.
ENSEMBLE SPREAD IS MODERATELY HIGH ACROSS THE FORECAST DOMAIN, PARTICULARLY
OVER THE WESTERN CONUS. THE GREATEST WEIGHTS IN THE WEEK-2 MANUAL HEIGHT BLEND
WERE GIVEN TO TODAY`S GEFS AND ECMWF ENSEMBLE MEAN SOLUTIONS BASED ON RECENT
SKILL AND ON ANALOG CORRELATIONS.
THERE ARE ENHANCED PROBABILITIES FOR BELOW NORMAL TEMPERATURES FOR MUCH OF THE
NORTHERN AND CENTRAL CONUS UNDERNEATH PREDICTED CYCLONIC FLOW. ABOVE NORMAL
TEMPERATURES ARE FAVORED FOR PARTS OF THE SOUTHWESTERN AND SOUTHEASTERN CONUS
UNDERNEATH PREDICTED NEAR TO ABOVE NORMAL HEIGHTS. THERE ARE ENHANCED
PROBABILITIES FOR BELOW NORMAL TEMPERATURES FOR MUCH OF SOUTHERN ALASKA (WITH
THE EXCEPTION OF THE ALEUTIANS) UNDERNEATH PREDICTED ANOMALOUS, NORTHERLY
500-HPA FLOW. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE ALEUTIANS
AND NORTHWESTERN ALASKA IN ASSOCIATION WITH PREDICTED RIDGING AND ABOVE NORMAL
HEIGHTS.
TELECONNECTIONS FROM THE PREDICTED POSITIVE 500-HPA HEIGHT ANOMALY CENTER NEAR
THE BERING STRAIT FAVOR ABOVE MEDIAN PRECIPITATION FOR THE WEST COAST OF THE
CONUS. ENHANCED PROBABILITIES FOR ABOVE MEDIAN PRECIPITATION ARE ALSO INDICATED
FOR THE EASTERN CONUS AND THE NORTHERN TIER UNDERNEATH PREDICTED CYCLONIC FLOW.
BELOW MEDIAN PRECIPITATION IS FAVORED FOR MUCH OF THE SOUTH-CENTRAL CONUS
CONSISTENT WITH DYNAMICAL MODEL GUIDANCE AND ANALOGS FROM THE MANUAL BLEND.
NEAR TO BELOW MEDIAN PRECIPITATION IS FAVORED FOR ALASKA IN ASSOCIATION WITH A
PREDICTED RIDGE.
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 20% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 10% OF TODAY`S OPERATIONAL 0Z GFS CENTERED ON DAY 11, 15% OF TODAY`S
OPERATIONAL 6Z GFS CENTERED ON DAY 11, 20% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, 5% OF YESTERDAY`S 12Z EUROPEAN ENSEMBLE MEAN CENTERED ON
DAY 10, AND 10% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE
TO AMPLITUDE AND PHASING DIFFERENCES AMONG THE MODEL SOLUTIONS AND MODERATELY
HIGH SPREAD AMONG THE COMPONENT ENSEMBLE MEMBERS.
FORECASTER: SCOTT HANDEL
NOTES:
AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL
INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES.
IN THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT
ISSUED.
THE NOTATION FOR THE CATEGORICAL FORECAST INDICATED ON THE MAPS IS
THE SAME AS THAT IN THE TABLES: A-ABOVE N-NEAR NORMAL B-BELOW
THE TEMPERATURE MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WARMER
(ORANGE, "A"), COLDER (BLUE, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL AVERAGE VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "F"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
THE PRECIPITATION MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING
WETTER (GREEN, "A"), DRIER (TAN, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL MEDIAN VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "INCHES"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
IN THE SOUTHWEST AND OTHER CLIMATOLOGICALLY DRY REGIONS - THERE WILL
BE A GREATER THAN 33.3% CHANCE OF NO PRECIPITATION AND OCCASIONALLY
EVEN A NORMAL (I.E. MEDIAN) VALUE OF ZERO - ESPECIALLY DURING THE DRY
SEASONS. IN SUCH CASES A FORECAST OF NEAR NORMAL IS EFFECTIVELY A
FORECAST OF LITTLE OR NO PRECIPITATION.
THE CLIMATE PREDICTION CENTER USES 1981-2010 BASE PERIOD MEANS FOR
TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN
THE CLIMATE OUTLOOKS.
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON
DECEMBER 15
ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19681221 - 20051202 - 19961219 - 19731126 - 19671219
ANALOGS TO THE 7 DAY MEAN OBSERVED PATTERN CENTERED 4 DAYS AGO (D-4)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 7 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
20051202 - 19681220 - 19961219 - 19671219 - 19731126
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 14 - 18 2016
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF A A IDAHO B A NEVADA A A
W MONTANA B A E MONTANA B A WYOMING B A
UTAH A A ARIZONA A N COLORADO B A
NEW MEXICO A N N DAKOTA B A S DAKOTA B A
NEBRASKA B A KANSAS B N OKLAHOMA B B
N TEXAS B B S TEXAS N B W TEXAS B B
MINNESOTA B A IOWA B A MISSOURI B N
ARKANSAS B N LOUISIANA N A WISCONSIN B A
ILLINOIS B A MISSISSIPPI B A MICHIGAN B A
INDIANA B A OHIO B A KENTUCKY B A
TENNESSEE B A ALABAMA N A NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B A
MASS B A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN A A AK N SLOPE A A
AK ALEUTIAN A B AK WESTERN N B AK INT BSN N N
AK S INT B B AK SO COAST B B AK PNHDL B B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 16 - 22 2016
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF N A
SRN CALIF A A IDAHO B A NEVADA N A
W MONTANA B A E MONTANA B A WYOMING B A
UTAH N A ARIZONA A A COLORADO N A
NEW MEXICO A B N DAKOTA B A S DAKOTA B A
NEBRASKA B A KANSAS B N OKLAHOMA B B
N TEXAS B B S TEXAS N B W TEXAS A B
MINNESOTA B A IOWA B A MISSOURI B N
ARKANSAS B N LOUISIANA N A WISCONSIN B A
ILLINOIS B A MISSISSIPPI N A MICHIGAN B A
INDIANA B A OHIO B A KENTUCKY B A
TENNESSEE B A ALABAMA N A NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B A
MASS B A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA N A GEORGIA N A
FL PNHDL A A FL PENIN A N AK N SLOPE A N
AK ALEUTIAN N B AK WESTERN B B AK INT BSN B N
AK S INT B B AK SO COAST B B AK PNHDL B B
LEGEND
TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN
A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN
B - BELOW B - BELOW
THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL
VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE
AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE.
FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS
PMDMRD.
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